Liquid crystal display devices have been used for watches and electronic calculators, various home electric appliances, measuring apparatuses, automotive panels, word processors, electronic notebooks, printers, computers, televisions, etc. Typical examples of a liquid crystal display mode include a TN (twisted nematic) mode, a STN (super twisted nematic) mode, a DS (dynamic light scattering) mode, a GH (guest-host) mode, an IPS (in-plane switching) mode, an OCB (optical compensated bend) mode, an ECB (electrically controlled birefringence) mode, a VA (vertical alignment) mode, a CSH (color super homeotropic) mode, and a FLC (ferromagnetic liquid crystal) mode, and the like. Also, drying methods include static driving, multiplex driving, a simple matrix method, and an active matrix (AM) method of driving by TFT (thin-film transistor), TFD (thin-film diode), or the like.
Among these display modes, the IPS mode, the ECB mode, the VA mode, or the CSH mode has the characteristic of using a liquid crystal material exhibiting a negative value of Δ∈. In particular, the VA display mode driven by AM driving is used for display devices, for example, a television and the like, which are required to have a high speed and a wide viewing angle.
Nematic liquid crystal compositions used for the VA display mode and the like are required to have low-voltage driving, fast response, and a wide operating temperature range. That is, the liquid crystal compositions are required to have a large absolute value of negative Δ∈, low viscosity, and a high nematic-isotropic liquid phase transition temperature (Tni). Also, in view of setting of Δn×d which is the product of refractive index anisotropy (Δn) and a cell gap (d), it is necessary to adjust Δn of a liquid crystal composition within a proper range according to the cell gap. In addition, when a liquid crystal display device is applied to a television or the like, fast response is regarded as important, and thus a liquid crystal composition having low viscosity (η) is required.
The characteristics of liquid crystal compositions have been improved by studying various compounds having negative Δ∈ and a large absolute value thereof.
A liquid crystal composition containing a compound represented by formula (A) and a compound represented by formula (B) is disclosed as a liquid crystal composition having negative Δ∈ (refer to Patent Literature 1).

The liquid crystal composition is intended to attain faster response by adding a compound (alkenyl compound) having an alkenyl group in its molecule, such as a compound represented by formula (B), but it is necessary to further increase the response speed and further research the requirement for high Δn.
A liquid crystal composition containing a compound represented by formula (C) and a compound represented by formula (D), which are substituted for the compound represented by the formula (A) in the liquid crystal composition described above, is disclosed (refer to Patent Literature 2).

Also, the liquid crystal composition is in a situation where the faster response is not satisfactorily achieved, and satisfactory improvement is not made in the need for high Δn.
On the other hand, a liquid crystal composition (refer to Patent Literature 3) including a combination of a compound represented by formula (E) and a compound represented by formula (F), which both have negative Δ∈, and a compound having substantially zero Δ∈ and represented by formula (I) is disclosed. However, this liquid crystal composition does not contain an alkenyl compound and thus has high viscosity and cannot satisfy the requirement for faster response. Also, in a process for manufacturing a liquid crystal display device, the compound represented by formula (I) having low vapor pressure is evaporated due to very low pressure when the liquid crystal composition is injected into a liquid crystal cell, and it is thus considered that the content of the compound cannot be increased. In addition, the upper limit temperature of a liquid crystal phase is decreased by adding the compound represented by formula (I), and thus the content of the compound represented by formula (I) in the liquid crystal composition is limited to only 2%, thereby causing the problem of very high viscosity while exhibiting large Δn. Therefore, it is demanded to satisfy both high Δn and low viscosity.
